1. Field of the Invention
The present invention relates generally to riding mowers and, more particularly, to an improved suspension system for such mowers.
Riding mowers have been a staple for maintaining highway rights of way for many years. They are seen moving along grassy center dividers and along the sides of roads in rough, sometimes rocky terrain, and in all sorts of attitudes from flat and level to severe side hills.
In many instances, an operator may be in the seat for hours, and even with a kidney belt, will suffer considerable discomfort and, in some cases, injury. Indeed, it is not inconceivable that the constant bouncing and jarring could cause an operator to lose control, resulting in damage to himself and others.
The underlying purpose and function of the present invention is to provide an element of relief to an operator and, coincidently, increased control.
2. Overview of the Prior Art
The typical riding mower in use today has its wheels affixed directly to the frame of the mower. In the late '90s the self proclaimed leader in the field, David Ferris, and others filed an application for a suspension system for riding mowers. The application claims priority based on provisionals, at least one of which dates back to 1996, and was divided and one of those continuations-in-part issued as Ferris et al. U.S. Pat. No. 6,460,318. The patent features a four bar mechanism relatively common in automotive suspensions. Another part of the original application is believed to be still pending.
Gordon U.S. Pat. No. 6,170,242 is yet another patent assigned to Ferris Industries and claims priority under a 1997 provisional, which is also claimed under the earlier mentioned Ferris et al. patent. Gordon, like Ferris et al., features a four bar mechanism.
A very early patent featuring a rubber bumper between two elements in an automotive structure is found in Hickman U.S. Pat. No. 3,737,174.
Several other patents offer variations on the same theme. See, for example, Dunlap et al. U.S. Pat. No. 3,669,467, which has additional buffering devices, such as springs, leaf or coil, and shock absorbing devices. Dunlap has a pair of cushions, but also uses a pair of rods 32 and 34, which attach directly to the frame rail.
Krakowiak et al. U.S. Pat. No. 5,979,920, uses the simple bumper between the frame rail and a leaf spring. This is a device which is common on many of the earlier motor vehicles.
Merkle U.S. Pat. No. 4,310,717, uses what he refers to as an elastomeric spring, again, between the frame rail and what he refers to as a web section which holds the axle upon which the wheel is connected. It appears in the drawing that there may be a shock absorber in the middle of this assembly.
Bonzer et al. U.S. Pat. No. 4,559,669, employs a resilient buffer 19 for a caster assembly. Heitzman U.S. Pat. No. 5,899,470 uses a couple of resilient buffers as part of a system for adjusting camber and caster. It is evident from these patents that using an elastomeric as a spring or shock absorber is not new in the art. All of these references seek, to a greater or lesser extent, some modulation of the amplitude and frequency of shock transmitted through a wheel of a vehicle, but are unsuited for a riding mower.